Hesperian Health Guides

Hesperian Health Guides

Managing the Way Water Flows

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HealthWiki > A Community Guide to Environmental Health > Chapter 9: Protecting Watersheds > Managing the Way Water Flows


When water flows into the ground or into waterways, it is called drainage. Good drainage reduces the dangers of flooding and erosion, and helps more water soak into the ground. Poor drainage causes soil erosion and stagnant water.

The best way to improve drainage is to make the surface water after a rainfall (called runoff) “walk off” rather than “run off,” so that it slows down, spreads out, and sinks into the ground. To do this:

right alt=Illustration of the below: Men use shovels to clean a drainage canal.
Regular cleaning of drainage channels helps prevent flooding and illness.
left alt=Illustration of the below: Gutters hanging from the roof of a house channel runoff into containers.
Turn rainwater into a household resource.


  • Collect runoff from roofs in cisterns and containers for drinking water, or direct it into ponds, fields, and gardens.
  • Maintain roadside plant life or build drainage channels alongside roads and keep them clear of blockages.

Watersheds in towns and cities

When a town or city is built, it changes the way water flows through the watershed. Urban development brings more hard surfaces such as roads, pavements, and roofs that cause rainwater to run off rather than to soak into the ground. This can cause water to collect and stagnate, providing places for mosquitoes to breed. It may also lead to flooding.

Where people gather in large numbers and industry develops, more pollution contaminates the water. Keeping wetlands and riverbanks healthy in towns and cities can be difficult, but it is especially important because wetlands prevent polluted water from collecting, contaminating plants and animals, and damaging human health.

To protect their part of the watershed, people in towns and cities can:

  • Safely dispose of human wastes and toxic chemicals to prevent them from polluting water sources and blocking water flow.
  • Restore riverbanks, streams, and wetlands as parks within the city. Some communities plant gardens alongside roads to help water sink into the ground, rather than drain into sewers.
  • Campaign to have city governments provide safer homes for people living in dangerous flood areas.
  • Pressure businesses and industries to take responsibility for their wastes.
  • Get involved through city government and civic organizations in regional planning and sustainable development efforts.
People in a city neighborhood clear trash from a drainage ditch and storm drain.
Watersheds in cities and towns are easily contaminated, but they can be protected!



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